1. Field of the Invention
The present invention relates to oil machinery, and particularly to a pumping and repairing unit which can be used for both oil pumping and well workover.
2. Description of the Related Art
Chinese Patent No. 200310100186.X discloses a pumping and repairing unit. The pumping and repairing unit comprises a head sheave shaft, a speed reducer, a larger gear, a small gear, an electric motor, a head sheave rope, a balance weight, a balance weight frame, guiding ropes, an oil pumping polished rod, a main frame, a supporting platform and a head sheave. A rope suspension device (or a polished rod eye) has an end connected with the polished rod, and another end connected with a periphery of a drum of the head sheave through a traction rope for the rope suspension device. The balance weight is fixed to the periphery of the drum of the head sheave through the balance weight frame, a rope hanging device, and a balance weight traction rope. The motor is coupled with the speed reducer through a brake and a coupling. An output shaft of the speed reducer is coupled with the small gear which meshes with the larger gear However, in the pumping and repairing unit with such a configuration, a hoisting barrel and a hoisting rope for workover offset far away from a center of a well so that an oil pipe is bent and a traction force is insufficient in the workover. Therefore, it is difficult for the pumping and repairing unit to be used for workover. In addition, when an electrical brake is disposed only at a high-speed end of a power transmission of the pumping and repairing unit, transmission components of the power transmission are subject to huge impact during braking, resulting in reduced lifetime and deteriorated performance of the pumping and repairing unit.